Device for Transferring Articles and Conveyor System Comprising Said Device

ABSTRACT

The invention relates to a device for transferring a transport car which can be displaced on a track system from a first track section of the track system that is arranged on a first level, to a second track section of the track system that is arranged on a second level different from the first level. The device comprises at least one first and one second transfer carriage which can carry at least one respective transport car to be transferred and which can be displaced in opposite directions on two different levels. The invention further relates to a conveyor system for transporting articles.

The invention relates to a device for transferring a transport car which can be moved on a track system from a first track section of the track system, which is arranged on a first level, to a second track section of the track system which is arranged on a second level different from the first level. Devices of this type are necessary for example in electric overhead conveyors, in which there are different sections of the track system which are arranged on different levels.

The invention moreover relates to a conveyor system for transporting articles having

-   -   a) a track system comprising a first track section, which is         arranged on a first level, and a second track section, which is         arranged on a second level different from the first level;     -   b) a plurality of driveable transport cars, by means of which at         least one article can be moved on the track system in each case;     -   c) a transfer device by means of which the transport cars can be         transferred from the first track section to the second track         section.

The height difference between track sections of a conveyor system of this type can be bridged for example by way of inclined track sections. However, the inclination of said inclined track sections with respect to a horizontal plane must not be too great so that a transport car can negotiate an ascending or descending section without difficulty. Accordingly, the length of this type of inclined track section in the transport direction is always dependent on the height difference to be negotiated between the two track sections of the track system which are arranged on different levels and the maximum possible inclination of an inclined section arranged between them

To save on this necessary installation space in the transport direction, devices of the type mentioned at the outset are sometimes used. Devices of this type which are known from the market comprise a transfer carriage which can be moved between a level associated with the lower track section and a level associated with the upper track section of the track system. The installation space required here in the transport direction is smallest when the transfer carriage is moved vertically.

If a transfer procedure is to take place for example from a lower track section to an upper track section of the track system, the transfer carriage receives a transport car from the lower track section, is moved to the upper track section and releases the transport car again there.

The now empty transfer carriage is then moved to the lower track section again where it receives a further transport car, and so on.

The throughput of a transfer device of this type is, however, limited. Particularly in electric overhead conveyors with a plurality of transport cars, situations can arise in which very many transport cars have to be transferred in as short a time as possible from a lower track section to an upper track section, or vice versa.

To increase the maximum throughput when transferring the transport cars, two parallel connected transfer devices of the type mentioned at the outset are normally used, with the track sections connected to the now two transfer devices by way of respective points. However, this solution is relatively expensive since two transfer devices and two points arrangements are required, with the latter additionally requiring corresponding control components.

Therefore, the object of the invention is to improve a device of the type mentioned at the outset to the effect that its throughput is increased in more economical manner.

In a device of the type mentioned at the outset, this object is achieved in that it comprises at least one first and one second transfer carriage which can each carry at least one transport car to be transferred and which can be moved in opposite directions between two levels.

The throughput of the device can be doubled as a result of the fact that the transfer device now comprises two transfer carriages which can be moved in opposite directions between two levels. To this end, the transfer carriages are arranged for example so that the one transfer carriage is located on a level associated with the upper track section of the track system when the second transfer carriage is located on a level associated with the lower track section of the track system. It is thus possible, for example, for a transport car to move onto the second transfer carriage at the bottom whilst a transport car which has already been transferred with the first transfer carriage can move onto the upper track section at the top. Whilst the second transfer carriage is then moved upwards, the first transfer carriage, in the meantime, can move downwards to the lower track section of the track system so that the positions of the two transfer carriages are switched. Then a transport car can move out of the transfer device again at the top, whilst a transport car moves into the transfer device at the bottom and the transfer procedure can be carried out again without the transfer carriage located at the top having to first of all move downwards for this, as is the case in known transfer devices.

Advantageous further developments of the invention are described in dependent claims.

It is particularly advantageous if the transfer carriages can be moved in each case along a vertical guide track. This minimises the installation space required for the transfer device in the transport direction.

In view of its counter-directional movement between the two levels, care must be taken to ensure that the two transfer carriages do not impede one another on their movement path, in particular that one of the transfer carriages does not collide with a transport car carried by the other transfer carriage. This is achieved in that at least one of the two transfer carriages has a carrying device for the transport car, which is mounted such it can pivot about a pivot axis. This measure enables obstructing components of the one transfer carriage to be pivoted out of the sphere of influence of the other, oncoming transfer carriage, or the transport car which is possibly carried by this, when the two transfer carriages move past one another in opposite directions.

It is particularly favourable here if the pivot axis extends horizontally.

In this connection, it can moreover be helpful if at least one of the two transfer carriages can be moved horizontally. This can also prevent a collision between the mutually approaching transfer carriages.

This can be effected, for example, in that the transfer carriages are guided by a carrying structure which can be moved horizontally. In this case, for example, the two transfer carriages are not moved relative to one another but are moved horizontally together with the carrying structure guiding them.

To this end, it is advantageous if the carrying structure runs in a horizontal guide track by means of rollers. It is thus possible to achieve a positively driven and precise movement.

In a modification, it is favourable if the vertical guide tracks for the transfer carriages comprise an upper section, a central section and a lower section and drive means are present by means of which the upper section and the lower section can be moved horizontally. In this case, the transfer carriages can be moved horizontally with the movable upper or lower section, thus enabling a relative movement of the two transfer carriages in the horizontal direction.

It is advantageous here if the drive means are arranged so that the transfer carriages can be moved horizontally independently of one another. It is thus possible to respond to particular situations when transferring the transport cars. It also enables easier maintenance.

It is particularly advantageous if the guide tracks comprise a first central section and a second central section which are arranged at a mutual spacing in the horizontal direction, wherein the upper section and the lower section of the vertical guide tracks can be moved in each case between a respective first position, in which these are aligned with the first central section, and a respectine second position in which these are aligned with the second central section. This means that a lower, a central and an upper track section is not associated with each of the two transfer carriages. Instead, the transfer carriages share a single lower section and a single upper section.

The object of the invention is moreover to provide a conveyor system of the type mentioned at the outset, which takes the above ideas into account.

This object is achieved by a conveyor system of the type mentioned at the outset in that

-   -   d) a transfer device according to one of claims 1 to 10 is         provided as the transfer device.

A transfer device according to the invention can be used particularly well and efficiently if the conveyor system is constructed in the manner of an electric overhead conveyor.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings, which show:

FIG. 1 a side view of a partial section of a conveyor system for transporting articles, wherein a device for transferring a transport car between two track sections arranged on different levels is shown schematically;

FIGS. 2 to 5 a view in each case in the transport direction of a first exemplary embodiment of the transfer device, wherein different phases of the transfer of transport cars from the lower track section to the upper track section of the track system are shown;

FIG. 6 a view corresponding to FIGS. 2 to 5 of a second exemplary embodiment of the transfer device;

FIG. 7 a view corresponding to FIG. 6 of a third exemplary embodiment of the transfer device;

FIG. 8 a view in the transport direction of a fourth exemplary embodiment of the transfer device;

FIG. 9 a side view of the transfer device of FIG. 8.

In Figure one, a conveyor system (of which a detail is shown) constructed in the manner of an electric overhead conveyor for transporting articles is denoted as a whole by 10. The conveyor system 10 comprises a track system 12 with a first carrying track 14 and a second carrying track 16 which extend at different heights over the level of a base 18. The first carrying track 14 is arranged on a first level which is located underneath a second level on which the second carrying track 16 is arranged.

The carrying tracks 14 and 16 are constructed as an I-shaped profile in conventional manner and are suspended in a manner known per se on a carrying assembly (not shown specifically here).

The conveyor system 10 moreover comprises a plurality of transport cars 20 of which three transport cars (20 a, 20 b, 20 c) are illustrated in FIG. 1 and which can be moved on the carrying tracks 14, 16. The transport direction in which material to be conveyed is transported along the carrying tracks 14, 16 by means of the conveyor system is indicated by arrows 22.

Contact lines (not shown specifically), which serve to supply power to the transport cars 20 and to transmit signals to these, extend along the carrying tracks 14, 16. Contact lines of this type correspond to the prior art.

Each transport car 20 comprises a travel mechanism 24 which reaches around the carrying track 14 or 16 and supports at least one carrying roller 26 (cf. FIGS. 2 to 7 and 9) which rolls along the top of the carrying tracks 14 or 16 and receives the load transported by the transport car 20. Each transport car 20 is driven by means of an electric motor (not shown specifically here) which is powered and controlled in conventional manner by way of the said contact lines. The travel mechanism 24 is prevented from tipping and tilting relative to a vertical and a horizontal plane by measures which are known per se.

To enable the transportation of articles by means of the transport car 20, this latter has a suspended transport means 28 which is connected to the travel mechanism 24 of the transport car 20 by way of a coupling element 30.

Located between the on the lower carrying track 14 and the upper carrying track 16, there is a transfer device (merely indicated schematically in FIG. 1) by means of which a transport car 20 arriving from the lower carrying track 14 can be lifted and transferred to the upper carrying track 16. By means of the transfer device 32, the transport car 20 can overcome the height difference between the lower carrying track 14 and the upper carrying track 16 without necessitating an ascending section of the track system 12 for this, which would need to have a larger extent in the transport direction 22 than the transfer device 32.

FIG. 2 shows a transfer station 34 as a first exemplary embodiment of the transfer device 32. This transfer station is constructed in the manner of a gantry and comprises a carrying frame 36 with a first vertical guide track 38 and a second vertical guide track 40. The vertical guide tracks 38 and 40 extend to the left and right (as seen in the transport direction) next to the vertical plane specified by the carrying tracks 14 and 16 arranged vertically above one another.

A first transfer carriage 42 is guided by means of the first vertical guide track 38 in such a way that it can only be moved in the vertical directions indicated in FIG. 2 by a double-headed arrow 44. To this end, the first transfer carriage 42 comprises a carriage travel-mechanism 46 which supports guide rollers 48 which cooperate with the first vertical guide track 38 and can each be rotated about a horizontal axis of rotation extending parallel to the transport direction 22.

An extension arm 50 is connected in articulated manner to the carriage travel-mechanism 46 and can be pivoted about a horizontal pivot axis 54, which extends parallel to the transport direction 22, between a carrying position and a no-load position (shown in FIG. 5) by way of a joint 52. That free end 56 of the extension arm 50 which is opposite the joint 52 carries a track piece 58 which has the same I-shaped profile as the carrying tracks 14 and 16. The dimensions of the extension arm 50 and the arrangement of the track piece 58 on this are determined such that the track piece 58 is arranged in the vertical plane specified by the carrying tracks 14 and 16 when the extension arm 50 of the first transfer carriage 42 assumes its carrying position. In the no-load position of the extension arm 50, this is pivoted upwards about the pivot axis 54 so that the track piece 58 finds itself at a spacing from the vertical plane specified by the carrying tracks 14 and 16. This will be discussed again below.

The transfer station 34 moreover comprises a second transfer carriage 60 which, in terms of its construction, corresponds substantially to the first transfer carriage 42, so components corresponding to those of the first transfer carriage 42 are denoted by the same reference numerals in the second transfer carriage.

The second transfer carriage 60 is also guided by its guide rollers 48 over the second vertical guide track 40 in such a way that it can only be moved in the vertical directions (cf. double-headed arrow 44).

Deviating from the first transfer carriage 42, the track piece 58 is not mounted directly on the free end 56 of the extension arm 50. Instead, the free end 56 of the extension arm 50 of the second transfer carriage 60 carries a holding structure 62 reaching around its track piece 58 so that the track piece 58 of the second transfer carriage 60 is carried from the same side as the track piece 58 is carried by the extension arm 50 of the first transfer carriage 42. A spacing therefore remains between the track piece 58 of the second transfer carriage 60 and the free end 56 of its extension arm 50 so that the travel mechanism 24 of a transport car 20 can move onto the track piece 58 of the second transfer carriage 60 and is thereby likewise surrounded by the holding structure 62 (cf. FIG. 5).

The extension arms 50 of the first and the second transfer carriage 42, 60 comprise a supporting strut 64 which abuts against the respective carriage travel-mechanism 46 when the corresponding extension arm 50 assumes its carrying position. Thus, for the transfer carriages 42 and 60, a further downward pivoting of the extension arm 50 is prevented when this occupies its carrying position.

The carrying frame 36 of the transfer station 34 comprises an overhead crossbeam 66 which supports two deflection rollers 68 and 70 which are each rotatable about a horizontal axis of rotation extending parallel to the transport direction 22. A drive pinion 74, which can be driven by means of an electric motor 72, is arranged between the deflection rollers 68 and 70. The in each case upwardly pointing end faces 76 of the transfer carriages 42 and 60 are connected to one another by way of a chain 78 which runs on the deflection roller 68, the drive pinion 74 and the deflection roller 70. The deflection rollers 68 and 70 are positioned so that the chain 78 extends substantially vertically downwards from the deflection roller 68 to the first transfer carriage 42 and substantially vertically downwards from the deflection roller 70 to the second transfer carriage 60.

In a modification, instead of the chain 78, it is also possible to use a cable, a belt or the like in conjunction with drive means which are adapted thereto and known per se.

The drive pinion 74 can be rotated optionally in a first direction indicated by the arrow 80 or in the opposing direction indicated by an arrow 82 by means of the electric motor 72. If the drive pinion 74 is rotated in the direction of the arrow 80, the first transfer carriage 42 moves upwards whilst the second transfer carriage 60 is moved downwards. If, on the other hand, the drive pinion 74 is rotated in the direction of the arrow 82, then the first transfer carriage 42 moves downwards and the second transfer carriage 60 moves upwards. The first and the second transfer carriages 42, 60 can be moved in opposite directions. In the present exemplary embodiment, this is effected in that the first and the second transfer carriages 42, 60 are coupled to one another by way of the chain 78.

The transfer station 34 described above now functions as follows:

In FIG. 2, the first transfer carriage 42 is shown in its bottommost position in which it is located on a first level. In this bottommost position of the first transfer carriage 42, its track piece 58 is in alignment with the lower carrying track 14 of the track system 12.

The second transfer carriage 60, on the other hand, assumes its topmost position in which it is located on a second level. In this topmost position the track piece 58 of the second transfer carriage 60 is in alignment with the upper carrying track 16 of the track system 12.

The transport car 20 a (cf. also FIG. 1) rolling on the lower carrying track 14 now arrives in the transfer station 34, whereupon it moves onto the track piece 58 of the first transfer carriage 42. In this position, the transport car 20 a is fixed on the track piece 58 of the first transfer carriage 42 by means of a braking device (not shown specifically here).

The drive pinion 74 is now moved in the direction of the arrow 80 by means of the electric motor 72 so that the first transfer carriage 42 with the transport car 20 a travels upwards and the empty second transfer carriage 60 travels downwards. This is shown in FIG. 3. If the second transfer carriage 60 moves downwards, its extension arm 50 is pivoted upwards by way of the joint 32, as shown in FIG. 3, so that the extension arm 50 with the holding structure 62 and the track piece 58 of the second transfer carriage 60 does not collide with the transport car 20 a held by the first transfer carriage 42. This pivotal movement of the extension arm 50 of the second transfer carriage 60 can be effected for example by means of an electric motor (not shown specifically here) or by means of a sliding guide which is known per se.

The first transfer carriage 42 is moved upwards with the transport car 20 a until it assumes its topmost position within the transfer station 34 in which it is located on the same level as the first transfer carriage 42 before in its topmost position (cf. FIG. 4).

The track piece 58 of the first transfer carriage 42 is now in alignment with the upper carrying track 16 of the track system 12. The transport car 20 a is now moved from the track piece 58 of the first transfer carriage 42 onto the upper carrying track 16 of the track system 12 and from there further to its destination.

At this point in time, the second transfer carriage 60 assumes its bottommost position in the transfer station 34, in which it is located on the same level as the first transfer carriage 42 in its bottommost position. With this, the extension arm 50 of the second transfer carriage 60 now assumes its carrying position again so that the track piece 58 is in alignment with the lower carrying track 14 of the track system 12 in the transport direction 22.

Whilst, at the top, the transport car 20 a descends from the first transfer carriage 42, a further transport car 20 d, at the bottom in the transfer station, moves onto the track piece 58 of the second transfer carriage 60. The drive pinion 74 is then moved in the direction of the arrow 82 by means of the electric motor 72, as a result of which the first transfer carriage 42 is moved in its empty state downwards and the second transfer carriage 60 is moved upwards with the transport car 20 d. The extension arm 50 of the first transfer carriage 42 also assumes its no-load position in which it is pivoted upwards about the pivot axis 54 when it is moved downwards.

The drive pinion 74 is moved in the direction of the arrow 82 until the first carriage 42 assumes its bottommost position (shown in FIG. 2) and the second transfer carriage 60 assumes its topmost position (likewise shown in FIG. 2) in the transfer station 34. The extension arm 50 of the first transfer carriage 42 is brought back into its carrying position. Whilst, at the top, the transport car 20 d now moves from the second transfer carriage 60 onto the upper carrying track 16 of the track system 12, at the bottom a further transport car 20 can move onto the first transfer carriage 42 and the procedure explained above can be repeated.

The transfer station 34 can also be used to transfer transport cars 20 from the upper carrying track 16 to the lower carrying track 14 of the track system 12. In this case, the extension arms 50 of the transfer carriages 42 and 60 each assume their no-load position when the transfer carriages are moved upwards. The extension arms 50 of the transfer carriages 42 and 60 are essentially brought into their no-load position when the transfer carriages 42 and 60 move past one another.

FIG. 6 shows a transfer station 1034 as a second exemplary embodiment of the transfer device 32. In this, components which correspond to those of the transfer station 34 according to FIGS. 2 to 5 are denoted by the same reference numerals plus 1000.

The transfer carriages 1042 and 1060 of the transfer station 1034 differ from the transfer carriages 42 and 60 substantially in that the respective extension arm 1050 is rigidly connected to the respective carriage travel-mechanism 1046.

The extension arms 1050 of the transfer carriages 1042 and 1060 are constructed so that their track pieces 1058 do not extend in a common vertical plane but, as seen in the transport direction 22, are arranged laterally offset from one another so that the transfer carriages 1042 and 1060 can move past one another without colliding with one another or without their respective extension arms 1050 colliding with one another.

So that a transport car 20 arriving from the lower carrying track 14 of the track system 12 can now be transferred to the upper carrying track 16, the carrying frame 1036 of the transfer station 1034 can be moved back and forth in a horizontal direction extending perpendicularly to the transport direction 22.

To this end, the carrying frame 1036 of the transfer station 1034 is mounted on rollers 1084 which roll in a guide track 1086 anchored to the base 18 of the conveyor system 10. The carrying frame 1036 of the transfer station 1034 is connected to the piston rod 1088 of a hydraulic cylinder 1090, as a result of which the carrying frame 1036 can be moved back and forth between two positions whereby, in one position, the track piece 1058 of the first transfer carriage 1042 and, in the other position, the track piece 1058 of the second transfer carriage 1060 can be in alignment with the lower carrying track 14 or the upper carrying track 16 of the track system 112.

During the transfer procedure, the carrying frame 1036 of the transfer station 1034 is, for example, firstly brought into a position in which the track piece 1058 of the first transfer carriage 1042, in its bottommost position, is in alignment with the lower carrying track 14 of the track system 12. Then a transport car 20 moves onto the first transfer carriage 1042 and, as explained above, is conveyed upwards until the track piece 1058 of the first transfer carriage 1042 is in alignment with the upper carrying track 16 of the track system 12.

The second transfer carriage 1060, which is located at this moment in its bottommost position in the transfer station 1034, is at this point in time laterally offset from the lower carrying track 14 of the track system 12.

After the transport car 20 has been moved from the first transfer carriage 1042 onto the upper carrying track 16 of the track system 12, a corresponding activation of the hydraulic cylinder 1090 causes the carrying frame 1036 of the transfer station 1034 to be moved into a position in which the track piece 1058 of the second transfer carriage 1060 located in its bottommost position is now in alignment with the lower carrying track 14 of the track system 12. A further transport car 20 can now move from the lower carrying tack 14 onto the second transfer carriage 1060 and be transferred accordingly to the upper carrying track 16 of the track system 12.

Then a corresponding activation of the hydraulic cylinder 1090 causes the carrying frame 1036 to be moved back into a position in which the first transfer carriage 1042, which now assumes its bottommost position in the transfer station 1034, is arranged such that its track piece 1058 is in alignment with the lower carrying track 14 of the track system 12.

FIG. 7 shows, as a further exemplary embodiment of the transfer device 32, a transfer station 2034 in which components which correspond to those of the transfer station 1034 of FIG. 6 have the same reference numerals plus 1000.

Instead of the carrying frame 1046, the transfer station 2034 has a carrying column 2092 which, on opposite sides, is constructed in each case as a vertical guide track 2038 or 2040 which cooperate with the first transfer carriage 2042 or the second transfer carriage 2060.

The chain 2078 is merely guided by way of the drive pinion 2074 here, which is dimensioned such that the chain 2078 extends in each case substantially vertically downwards to the respective transfer carriage 2042 or 2060.

Whilst, in the transfer stations 34 and 1034, the extension arms 50 or 1050 of the transfer carriages 24 and 60 or 1042 and 1060 each face towards one another, the extension arms 2050 of the transfer carriages 2042 and 2060 of the transfer station 2034 face away from one another.

Otherwise, the transfer station 2034 functions in the manner explained above with regard to the transfer station 1034 according to FIG. 6.

FIGS. 8 and 9 show, as a further exemplary embodiment of the transfer device 32, a transfer station 3034 in which those components which correspond to the those of the transfer station 2034 according to FIG. 7 are denoted by the same reference numerals plus 1000.

The transfer station 3034 comprises a carrying structure 3094 which is anchored laterally next to the carrying tracks 14, 16 of the track system 12 at the base 18 of the conveyor system 10.

A front vertical guide track 3096, which is constructed as an I-shaped profile, is mounted on the front side of the carrying structure 3094, which faces the carrying tracks 14, 16, and a constructionally identical rear vertical guide track 3098 is mounted on the rear side of the carrying structure 3094, which is remote from the carrying tracks 14, 16. Theses guide tracks 3096, 3098 extend in a region 3100 above the lower carrying track 14 of the track system 12 and below the upper carrying track 16 of the track system 12, are the same length and are aligned flush with one another in each case at the top and bottom.

Arranged above the guide tracks 3096, 3098, there is an upper vertical guiding track 3102, whereof the cross-section corresponds to those of the guide tracks 3096 and 3098. The upper guiding track 3102 can be moved horizontally between a rearmost position, in which it is in alignment with the rear guide track 3098, and a frontmost position, in which it is in alignment with the front guide track 3096. To this end, the upper guiding track 3012 is rigidly coupled to a piston rod 3108 of a correspondingly aligned hydraulic cylinder 3110 which acts as a displacing device. The upper guiding track 3102 thus follows the translatory movement of the piston rod 3108. Moreover, the rigid coupling between the upper guiding track 3102 and the piston rod 3108 prevents the upper guiding track 3102 from tilting with respect to a vertical plane.

Analogously, a lower vertical guiding track 3112, whereof the cross-section corresponds to that of the guide tracks 3096, 3098 and the upper guiding track 3012, is arranged below the guide tracks 3096. The lower guiding track 3112 can also be moved horizontally between a rearmost position, in which it is in alignment with the rear guide track 3098, and a frontmost position, in which it is in alignment with the front guide track 3096. To this end, the lower guiding track 3112 is rigidly coupled to a piston rod 3118 of a correspondingly aligned hydraulic cylinder 3120 which acts as a displacing device for the lower guiding track 3112.

The two transfer carriages 3042 and 3060 in this exemplary embodiment are constructionally identical, i.e. in both transfer carriages 3042, 3060 the free end of the extension arm 3050 caries the track piece 3058. The transfer carriages 3042 and 3060 run in the guide tracks 3096, 3098 or the guiding tracks 3102, 3112, wherein their carriage travel-mechanisms 3046 are constructed such that these reach around the guide tracks 3096, 3098 or the guiding tracks 3102, 3112. Their extension arms 3050 each project in the direction of the carrying tracks 14, 16 of the track system 12.

The first and the second transfer carriages additionally support lateral guide rollers 3104 and 3114 (cf. FIG. 8) which can roll in upper horizontal tracks 3106, which are arranged on the level of the upper guiding track 3102, and lower horizontal tracks 3116, which are arranged on the level of the lower guiding track 3112.

The transfer station 3034 comprises two deflection rollers 3122, 3124 which are mounted at the bottom of the carrying structure 3094 and are fixed to a common drive shaft 3126 which can be driven by means of an electric motor 3128. The axis of the drive shaft 3126 extends parallel to the transport direction 22 of the conveyor system 10.

Moreover, the transfer station 3034 comprises an upper deflection roller 3130, which is mounted at the top of the carrying structure and is arranged in vertical alignment with the lower deflection roller 3122, and a further upper deflection roller 3132, which is mounted at the top of the carrying structure and is arranged in vertical alignment with the lower deflection roller 3124. The upper deflection rollers 3130, 3132 are not driven.

A continuous chain 3134 runs over the deflection roller pair 3122, 3130 arranged vertically above one another and a continuous chain 3136 runs over the deflection roller pair 3124, 3132 arranged vertically above one another. The continuous chains 3134 and 3136 are provided with carriers (not shown specifically here) which can cooperate with the transfer carriages 3042 and 3060.

Provided adjacent to the ends of the upper horizontal tracks 3106 and the lower horizontal tracks 3116, there are upper stops 3138 and lower stops 3140 which cooperate with the lateral guide rollers 3104 and 3114 of the transfer carriages 3042 and 3060 in a manner explained further below.

The transfer station 3034 functions as follows:

In the phase of the transfer procedure shown in FIGS. 8 and 9, the upper guiding track 3102 has been displaced into its rearmost position by way of a corresponding activation of the hydraulic cylinder 3110. The first transfer carriage 3042 is located with its guide rollers 3048 in the upper guiding track 3108 and lies with its lateral guide rollers 3104 and 3114 against the upper stops 3138, thus preventing a further upward movement of the first transfer carriage 3042.

The lower guiding track 3112 has been displaced into its frontmost position by way of a corresponding activation of the hydraulic cylinder 3120 associated with it. The second transfer carriage 3060 is located with its guide rollers 3048 in the lower guiding track 3108 and assumes a vertical position in which its track piece 3058 is in alignment with the lower carrying track 14 of the track system 12 of the conveyor system 10. With this, it lies with its lateral guide rollers 3104 and 3114 against the lower stops 3140, thus preventing a downward movement of the second transfer carriage 3060.

A transport car 20 of the conveyor system 10 has already moved from the lower carrying track 14 of the track system 12 onto the second transfer carriage 3060 or onto its track piece 3058.

The lower deflection rollers 3122, 3124 are now rotated by means of the electric motor 3128 in such a way that the first transfer carriage 3042 travels downwards and the second transfer carriage 3060 with the transport car 20 travels upwards. To this end, the above-mentioned carriers (not shown specifically) of the continuous chains 3134 and 3136 each engage with the transfer carriages 3042, 3060 so that these are carried in the movement direction of the corresponding strand of the continuous chains 3134, 3136.

With this, the first transfer carriage 3042 travels out of the upper guiding track 3102 into the rear guide track 3098 and the second transfer carriage 3060 travels out of the lower guiding track 3112 into the front guide track 3096.

Whilst the transfer carriages 3042, 3060 are guided by the rear or front guide tracks 3098 and 3096, the upper guiding track 3102 is pushed by means of the hydraulic cylinder 3110 associated therewith into its frontmost position and the lower guiding track 3112 is pushed by means of the hydraulic cylinder 3120 associated therewith into its rearmost position.

Then, the second transfer carriage 3060 with the transport car 20 travels out of the front guide track 3096 into the upper guiding track 3102 and the unladen first transfer carriage 3042 travels out of the rear guide track 3098 into the lower guiding track 3112. The lower deflection rollers 3122, 3124 are driven until the second transfer carriage 3060 lies with its lateral guide rollers 3104 and 3114 against the upper stops 3138 on the front side of the carrying structure 3094. In this position, the track piece 3058 of the second transfer carriage 3060 is in alignment with the upper carrying track 16 of the track system 12 of the conveyor system 10.

After this, the transport car 20 travels from the second transfer carriage 3060 onto the upper carrying track 16 of the track system 12 and from there to its destination.

Meanwhile, the lower guiding track 3112, together with the first transfer carriage 3042 guided therein, is pushed by means of the hydraulic cylinder 3120 associated therewith into its frontmost position. Here, the first transfer carriage 3042 lies firstly with its lateral guide rollers 3104, 3114 on the lower stops 3140 on the rear side of the carrying structure 3094. Then it travels with its lateral guide rollers 3104 and 3114 into the lower horizontal tracks 3116. This prevents a downward movement of the transfer carriage 3042 in the lower guiding track 3112. Finally, the first transfer carriage 3042 comes to lie with a lateral guide rollers 3104, 3114 on the lower stops 3140 on the front side of the carrying structure 3094. Here, the first transfer carriage 3042 is aligned vertically so that its track piece 3058 is in alignment with the lower carrying track 14 of the track system 12, towards which a further transport car 20 is already moving.

This further transport car 20 now moves onto the first transfer carriage 3042. At the same time, the upper guiding track 3102, together with the second transfer carriage 3060, is pushed into its rearmost position which takes place in the manner explained above with regard to the horizontal movement of the first transfer carriage 3042. The situation now corresponds to that shown in FIGS. 8 and 9, save that the positions of the first and the second transfer carriage 3042 and 3060 are switched.

The transfer procedure explained above is now repeated accordingly. 

1. A device for transferring a transport car which can be moved on a track system from a first track section of the track system, which is arranged on a first level, to a second track section of the track system which is arranged on a second level different from the first level wherein the device comprises at least one first transfer carriage and one second transfer carriage which can each carry at least one transport car to be transferred and which can be moved in opposite directions between two levels.
 2. The device of according to claim 1, wherein the transfer carriages can be moved in each case along a vertical guide track.
 3. The device of claim 1, wherein, at least one of the transfer carriages has a carrying device for the transport car, which is mounted such that it can pivot about a pivot axis.
 4. A device according to claim 3, characterised in that the pivot axis extends horizontally.
 5. The device of claim 1, wherein at least one of the transfer carriages can be moved horizontally.
 6. The device of claim 5, wherein the transfer carriages are guided by a carrying structure (1036; 2092) which can be moved horizontally.
 7. The device of claim 6, wherein the carrying structure runs in a horizontal guide track by means of rollers.
 8. The device of claim 5, wherein vertical guide tracks for the transfer carriages comprise an upper section, a central section and a lower section and drive means are present by means of which the upper section and the lower section can be moved horizontally.
 9. The device of claim 8, wherein that the drive means are arranged so that the transfer carriages can be moved horizontally independently of one another.
 10. The device of claim 8, wherein the vertical guide tracks comprise a first central section and a second central section which are arranged at a mutual spacing in the horizontal direction, wherein the upper section and the lower section of the vertical guide tracks can be moved in each case between a respective first position, in which these are aligned with the first central section, and a respective second position in which these are aligned with the second central section.
 11. A conveyor system for transporting articles comprising: a track system comprising a first track section, which is arranged on a first level, and a second track section, which is arranged on a second level different from the first level; a plurality of driveable transport cars, by means of which at least one article can be moved on the track system in each case; and, the transfer device of claim
 1. 12. A conveyor system according to claim 11, wherein the conveyor system is an electric overhead conveyor. 